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F. SIMPSON ET AL SHIPS DAViT Filed Sept. 5, 1921 5' Shegts-Sheat" IMF/470m.-

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Wiay 201 19249 F.' SIMPSON -ET AL sHIPs DAVIT 5 Sheets-Sheet 5 Filed Sept. 5. 1921 WOW I H A riving1-pinieaga1apad to gear-"withf one' Patented May 20, 1924.

UNITED STATES PATENT OFFICE.

FRED SIMPSON, or BLUNDELLSANDS, NEAR LIVERPOOL, AND ARTHUR ROBERT I THOMAS woons, or nnnrronn, ENGLAND.

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Application filed September 3, 1921.

T 0 all whom it may concern:

Be it known that we, FRED SIMrsoN and ARTHUR ROBERT THOMAS Woons, subjects of the King of Great Britain, residing, respectively, in Blundellsands, near Liverpool, in the county of Lancaster, England, and Hertford, England, have invented certain new and useful Improvements in and Relating to Ships Davits, of which the following is a specification.

This invention relates to means for connecting together and for operating ships davits, and is particularly to the type of gear described in the specification to- British Letters Patent No. 113,625 granted to us, and the object is to simplify such gear by reducing the number of parts and space occupied and to provide a gear which shall be specially applicable to existing davits.

In our said specification we employ two pairs of linked segmental worm-wheels driven by a Worm-shaft, there being one pair of worm-wheels for each davit; this construction necessitates one of the worm-wheel segments being mounted on each davit, and the provision of a horizontal worm-driving shaft extending from one davit to the other.

According to the present invention, instead of fitting a pair of linked worm-wheel segments to each davit, we employ a single pair only, of such linked segments disposed close together and driven by a short length of worm-shaft, this gear being located in a convenient position between the two davits. The segments, their linkage and the worm or worms on the shaft are so arranged that on operating the shaft the co-ordinated movement which it is desired to impart to the davits is imparted in the first instance to the segments, the respective segments being connected to the davits by suitable gear, say drums and endless ropes or chains and engaging and disengaging gear, in such manner that the davits may be operated by the gear or be freed from the gear so as to be operated independently.

It has been proposed in the case of two drums respectively connected by endless ropes to collars fixed on the davits, to 0peratethe drums by means of elliptic gears connected to the, respective drums, or by means of 'linked mutilated pistons connected-f to the respective drumsland gpemteeby a" of the mutilated pin-ions and aainteraiedate Serial No. 498,441.

pinion driven by the driving pinion and adapted to gear with the other mutilated pinion. g

I In carrying out the present invention drums and endless chains or wire ropes are employed to transmit the motion of the Worm-wheel segments, linked together and operated by a worm or worms, to two drums rotatably mounted on bearings fixed to the ships structure independentlyof the davits; these bearings are usually hollow flanged bosses mounted so that the respective davits pass through the bores thereof concentrical- 1y but leaving sulficient clearance between the davits and the said bores to permit of the deflection of the davits relatively to the said bearings, so that the said drums have v fixed centres of rotation which are not af fected by davit deflection, in this way the latter deflection does not affect the tension of the rope or chain connecting the said drums to the worm wheel drums. The connection between the davit and the drum rotatably mounted in respect to the davit is made by means of engaging and disengaging gear fitted between a coupling part fixed to the davit and the independently mounted drum, said gear being preferably of the type described in the complete specification of our application for a Patent No. 20138 of 1919.

We prefer to connect the drums by means of wire rope, and the drums are doublegrooved and have a central clamping groove running from the one groove to the other in which central groove the rope is securely attached to the drum by clamping bolts.

Usually the short worm-driving shaft is arranged so that in plan its axis cuts the line joining the centres of the segmental worm-Q wheels at a point between these centres, and preferably the said axis may be inclined to the said line at right angles,i n which case a single worm suflices for both wormwheels.

The operatlng gear is positive in the sense that each davit is under control throughout the whole of its movement and the 'co-ordinated movement between the davits is effected independently of any guy-rope connection betweenthe'two davit heads,"

Theiinvention is illustrated cqmpanying d rawiln'gsin Whichf- 1 of the linked worm gear, the davit operating drums and the davi-ts.

Figs. 8 to 6 are diagrammatic views to a smaller scale than Fig. 2, showing the position of the gear at different points in the movement.

Fig. 7 is a view similar to Fig. 2 and shows a modification.

Figs. 8, 9, 10 and 11 are detail views of the davit operating drums with the rope fastening gear, the coupling members-,and the engaging and disengaging gear. a

Fig. 8 is a plan view; Fig. 9 an elevation in section on the line IX, IX of Fig. 8; Fig. 10 an outside elevation on a plane of projection normal to the arrow Z; and Fig. 11 a fragmentary section on the line XI,XIofFig. 8. i

Referring first to Figs. 1 to 6 and 8. to 11, which illustrate theypreferred form, A and B are respectively, say, the: foreeandhft davits, andG a d D arczt e fore-and aft worm-wheel segments. These segments are mounted on discs 0- andqol and-may 'initially be angularly adjustable-on the said discs so that the same. gear may be E made to suit different arrangements of davits; the discs 0 and al are rotat2ubly mounted on vertical studs 0 and d carriedfrom a bed-plate E and'the discs are provided with a worm-wheel G carriedon a worm shaft mounted in bearings 9 carried from the bed-plate E and fitted with suitable thrust bearings, one end of theshaft G is fitted with the universal coupling g one of the elements of the coupling having a shaft g which extends to an" operating pillar 5 (see Fig. 1) where it is connected by a second universal coupling 9' to a shaft mounted in this pillar and operated through suitable gear and handles g of and d are fixed limitingstops against which the respective ends-of the connecting rod F engage -(see right hand end Fig. 2) in extreme in-board and out-board positions of the gear. On the under-side, and attached to the discs or formed integral therewith are rope-drums H the construction of which is similar-to the davit operating rope-drums H to be subsequently described. a

K are coupling members rigidly attached to the respective davits, H :are the davit operating'rope-drums, one for each davit; these rope-drums are rotatably mounted on the bosses of hollow bearings h secured by flanges [L to the structure ofthe ship, say by means of an attachment-plate.

The drums are-provided with gun-metal bushes h". The bore of the bearingmis 0011..

ntric ith h d it bu is substan ia ly larger in diameter than the davit so that deflection of the latter does not affect the bearing of the rope-drums and therefore has no effect on the tension of the ropes connecting the rope-drums H and H together.

Each rope-drum H has two normal grooves, an upper groove h and a lower groove h and at one part of the circumference these two grooves are joined by a centre groove h with oblique ends (see Figs. 8 to 11); the rope is led on to the normal portion of the upper groove h, it then passes somewhat more than half way round this groovefthen through the centre groove h into the lower groove h", passing somewhat more than half way round this groove and then off the drum. The portion of the rope in the centre groove h is clamped to the drum by the clamping bolts k thus in addition to the wrapping friction between the rope and the rope drum, the rope is positively attached to the drum by means which permit of its adjustment.

The coupling members K consist of semicircular'lugs caused to grip the davit by tightening bolts 10 and a pinching screw 20 and the straightportions of the lugs are carried beyond the bolts so as to form jaws 70 to take the connecting and disconnecting gear next to be described.

Each of the davit operating rope-drums H is provided with two pairs of lugs 71. in each of which a bell-crank tumbler h is pivoted on a pin h. When the tumblers are each turned into the position shown in full lines in Fig. 9, their engaging parts engage with the respectively opposite jaws 70 of the coupling members K, and they thus connect the davit operating ropedrums non-rotationally with the respective davits through the couplings K; the connection is such as to couple these parts in definite angular relationship whilst permitting a certain freedom of transverse movement of the davit due to deflection when the latter is loaded.

When each of the tumblers is turned into the position shown in chain dotted lines on the right hand side of Fig. 9, it will be seen that the davit is left quite free from the davit operating rope-drum, so that in the event of the gear becoming deranged the davits may be'left practically free to be operated individually in the usual manner. Each tumbler is fitted with a locking pin it which is adapted, by engagement with the top of the lugs it" to hold the tumbler in engagement as shown in full lines in Fig. 9, or, by engagement of the sides of the lugs to-hold the tumbler out of engagement when in the position shown in chain-dotted lines on the right hand side of Fig. 9. In order to ensure that the coupling K can be fixed to the drum H in the one angular position only, the engaging parts of the tumbler may be so shaped that each will enter one only of the en a 'in 'aws li lubrication between As stated, each ofithe discs 0 and d of the respectiveworm-segments C and D is fittedwith a rope-drum H bolted thereto or integral therewith; and each of these drums has grooves corresponding with the upper groove if, the lower groove 72. and the centre groove 7L7 described in connection with the drum H, and the centre grooves of the drum H are fitted with clamping bolts similar to the bolts 71 described in connection with the drum H, so that the connecting rope R is positively attached to a davit drum H and to a segment drum H as shown; the rope passing from an upper groove in H to an upper groove in H, then passing sowemhat more than half round this groove, then through the centre groove into the lower groove, then somewhat more than half round this groove, to the lower groove in H, then somewhat more than half way round this groove, then through the centre groove in H into the upper groove, and somewhat more than half way round this groove, then to the, drum H.

The angular extent of the'grooves h and h is such as to permit the necessary angular movement of drums without the rope leav-' ing these grooves.

The action is as follows Referring to Figs. 2 to 6;

Assuming 0 and d to be the centres of motion of the worm segments, it will be seen that the linkage connecting these together is the arm 0 0 the rod F, the length of which is 0 (Z and the arm d d. In Fig. 2 the davits A and B are in their in-board position, and it will be seen that the davit arms are in this P sition practically parallel respectively with the arms 0 0 and d d and that the worm seg ment D is in gear with the worm G, the segment C being free. When the gear is operated by the handle the worm is rotated and moves the segment D into the position shown in Fig. 3 where the rod F and the arm 61 (Z are in line, the davit A having been moved by the linkage into its extreme position to the left with the davit head at a whilst the head of the davit B is at 6 Continued movement of the operating gear moves the segment D into the position shown in Fig. 4, the rod F is now practically normal to the two crank arms, the head of the davit A has been moved back to the posi tion a and the head of the davit B has been moved to b; the segment C and segment D are in this position both in engagement with the worm G; further movement of the operating handle causes the worm to engage with segment C leaving the segment D free and this latter segment is moved by the linkage into the position shown in Fig. 5 where the arm '0 a is n line with the rod F, the davit heads being movedinto the positions a and 5 shown.

Further movement-of the gearmoves the segment G into the position shown in Fig. 6, in which the head of the davit A has been moved forward to its out-board positio'nqf and the headof the davit B drawn back to its in-boardposition it will be noted that in this position as well as in each intermediate position the davit arms are 'practically parallel with the respective farms randam; i 1

By the operation of thehandle g in the reverse direction the davit heads are moved back to the in-boardposition. i

7 It will be seen that the 'engagement'ofi the heads of the respective ends of the rod F with the respective limit stops 0 and d definitely limits the movement of the gear at the end of the out-board and in-board movements respectively. I

It will also be seen that the coordinated movements of the davit arms are those necessary in launching the boat and that each davit is positively and mechanically held under control by the operating gear throughout its co-ordinated' movement.

In the arrangement described the two segments are brought sufliciently near together to enable them to gear with the one worm. In some cases .it may not be possible to do this, and in these cases the modification shown in Fig. 7 is provided. In this modification there are two worms G and G these are mounted on a worm shaft carried in end bearings 9 with a centre thrust bearing 9 these hearings being mounted on a bed-plate E the shaft being provided with, say, a squared part 9 to which a handle is fitted by which the gear is operated. In other respects the gear is constructed and operates in the manner above described. In Fig. 7 the ropes are shown as being fitted with turn-buckles M comprising right and left handed screws, and a connecting sleeve nut, and these may be used totake up any slack rope.

These turn-buckles may be fitted to the arrangements first described. In some cases a spring buffer (no-t shown) may also be fitted to each length of rope, and these may also be fitted to the arrangement first described.

Each of the arrangements described is specially suitable for application to existing davits. The central portion comprising the bed-plate E, the segments and their operating gear may be fitted in any convenient position, and the operating shaft 9 may be carried to an operating pillar 9 located in a position best adapted for manipulating the gear.

The details of construction may be varied to suit different arrangements.

&

Having now fully described our invention, we declare that what we claim and desire to secure by Letters Patent is l. A device of the character described, includin a pair of davits, a rotatable member secure to each davit, means to rotate said members, including two spaced apart worm wheel segments, a connecting rod pivotally mounted on each segment and joining the same, and a single rotatable member engageable by each segment for rotating said segments.

2. The device of claim 1, said single rotatable member engaging said segments alternately. 1

3. The device of claim 1, said single rotatable member having its axis of rotation at right angles to the axes of rotation of said segments.

4:. The device of claim 1, said single rota- 20 lVitnesses t0 the signature of FredSimpson: v

G. F. SIMPSON. J. H. Dunosr.

Witnesses to the signature of Arthur Robert Thomas Woods:

M. Donn, S. M. SINGLE. 

